Botulism

Botulism

Definition

Botulism is an acute, progressive condition caused by botulinum toxin, a natural poison produced by the spore-forming bacteria Clostridium botulinum. Exposure to the botulinum toxin usually occurs from eating contaminated food although, in infants, it may be caused by specific types of clostridia obtained from soil or inhaled spores, causing growth of the bacteria in the infant's intestine. Botulinum toxin is a neurotoxin that blocks the ability of motor nerves to release acetylcholine, the neurotransmitter that relays nerve signals to muscles, a process that may result in unresponsive muscles, a condition known as flaccid paralysis. Breathing may be severely compromised in progressive botulism because of failure of the muscles that control the airway and breathing.

Description

Botulism occurs only rarely, but its high fatality rate makes it a great concern for those in the general public and in the medical community. Clinical descriptions of botulism reach as far back in history as ancient Rome and Greece. However, the relationship between contaminated food and botulism was not defined until the late 1700s. In 1793 the German physician, Justinius Kerner (1786–1862), deduced that a substance in spoiled sausages, which he called wurstgift (German for sausage poison), caused botulism. The toxin's origin and identity remained vague until Emile van Ermengem (1851–1932), a Belgian professor, isolated Clostridium botulinum in 1895 and identified it as the source of food poisoning .

Three types of botulism have been identified: food-borne, wound, and infant botulism. The main difference between types hinges on the route of exposure to the toxin. Food-borne botulism accounts for 25 percent of all botulism cases and can usually be traced to eating contaminated home-preserved food. Infant botulism accounts for 72 percent of all cases. About 98 percent of infants recover with proper treatment. Although domestic food poisoning is a problem worldwide, concern is growing regarding the use of botulism toxin in biological warfare. At the end of the twentieth century 17 countries were known to be developing biological weapons, including the culture of botulism toxins.

Transmission

Botulism is not spread from one individual to another, but through exposure to the deadly botulinum toxin, a natural poison produced by certain Clostridium bacteria that may be found in preserved, especially canned, foods and sometimes in the intestines of infants. Botulism spores can cause widespread illness if introduced into the environment.

Demographics

Botulism occurs worldwide, with 90 percent of the comparatively rare cases occurring in the United States. Approximately 110 cases of botulism are reported annually in the United States, with 50 percent of cases in California alone. Infant botulism accounts for 72 percent of all cases, far exceeding both food-borne and wound botulism. Food-borne botulism accounts for 25 percent of all cases, primarily due to eating contaminated home-preserved food.

Causes and symptoms

Toxins produced by the bacterium Clostridium botulinum are the main culprit in botulism. Other members of the Clostridium genus can produce botulinum toxin, namely C. argentinense, C. butyricum, and C. baratii, but these are minor sources. To grow, these bacteria require a low-acid, oxygen-free environment that is warm (40–120°F or 4.4–48.8°C) and moist. Lacking these conditions, the bacteria transform themselves into spores that, like plant seeds, can remain dormant for years. Clostridia and their spores exist all over the world, especially in soil and aquatic sediments. They do not threaten human or animal health until the spores encounter an environment that favors growth. The spores then germinate, and the growing bacteria produce the deadly botulism toxin.

Scientists have discovered that clostridia can produce at least seven types of botulism toxin, identified as A, B, C, D, E, F, and G. Humans are usually affected by A, B, E, and very rarely F; infants are affected by types A and B. Domesticated animals such as dogs, cattle, and mink are affected by botulism C toxin, which also affects birds and has caused massive die-offs in domestic bird flocks and wild waterfowl. Botulism D toxin can cause illness in cattle, and horses succumb to botulism A, B, and C toxin. There have been no confirmed cases of human or animal botulism linked to the G toxin.

In humans, botulinum toxin latches onto specific proteins in nerve endings and irreversibly destroys them. These proteins control the release of acetylcholine, a neurotransmitter that stimulates muscle cells. With acetylcholine release blocked, nerves are not able to stimulate muscles. Ironically, this action of the botulinum toxin has given it a beneficial niche in the world of medicine. Certain medical disorders are characterized by involuntary and uncontrollable muscle contractions. Medical researchers have discovered that injecting a strictly controlled dose of botulinum toxin into affected muscles inhibits excessive muscle contractions. The muscle is partially paralyzed and normal movement is retained.

Human botulism (caused by botulism toxins A, B, and E) may stem from contaminated food, wound contamination, or the intestinal botulism toxin found in infants. Each produces multiple symptoms as follows:

Food-borne botulism. Food that has been improperly preserved or stored can harbor botulinum toxin-producing clostridia. Canned or jarred baby food has also been known to cause botulism. Symptoms of food-borne botulism typically appear within 18 to 36 hours of eating contaminated food, with extremes of four hours to eight days. Initial symptoms include blurred or double vision and difficulty swallowing and speaking. Possible gastrointestinal problems include constipation , nausea , and vomiting . As botulism progresses, the victim experiences weakness or paralysis, starting with the head muscles and progressing down the body. Breathing becomes increasingly difficult. Without medical care, respiratory failure and death are very likely.

Infant botulism. Infant botulism was first described in 1976. Unlike adults, infants younger than 12 months are vulnerable to C. botulinum colonizing the intestine. Infants ingest spores in honey or simply by swallowing spore-containing dust or dirt. The spores germinate in the large intestine and, once colonized, toxin is produced and absorbed into the infant's body from the entire intestinal tract. The first symptoms include constipation, lethargy, and poor feeding. As infant botulism progresses, sucking and swallowing (thus eating)
become difficult. A nursing mother will often notice her own breast engorgement as the first sign of her infant's illness. The baby suffers overall weakness and cannot control head movements. Because of the flaccid paralysis of the muscles, the baby appears floppy. Breathing is impaired, and death from respiratory failure is a very real danger.

Wound botulism. Confirmed cases of wound botulism have been linked to trauma such as severe crush injuries to the extremities, surgery, and illegal drug use. Wound botulism occurs when Clostridia colonize an infected wound and produce botulinum toxin. The symptoms usually appear four to 18 days after an injury occurs and are similar to food-borne botulism, although gastrointestinal symptoms may be absent.

When to call the doctor

Infant botulism may be hard for parents to identify because the symptoms occur slowly. Parents should call the doctor or take the infant or child to emergency services as soon as the child shows symptoms such as weakness or listlessness, lethargy, irritability, and poor eating (or nursing) along with decreased bowel movements or constipation. An affected child may be so weak as to appear floppy and not in control of muscle movements, especially movement of the neck and head. Whether parents are aware of a possible source of the botulism toxin, the suggestive symptoms should not be ignored.

Diagnosis

Differential diagnosis of botulism can be complex because the symptoms mimic those of other diseases, especially diseases characterized by muscle weakness. Botulism must be differentiated from diseases such as the following:

Sepsis is the most common initial diagnosis for actual infant botulism, and meningoencephalitis may also be the diagnosis if irritability and lethargy are present. Infant botulism was at one time linked to 5 to 15 percent of cases of sudden infant death syndrome (SIDS, crib death) because of spores found in 4 to 15 percent of cases; however, a subsequent 10-year study did not find a significant influence of botulism on SIDS.

Laboratory tests are used to make a definitive diagnosis, but if botulism seems likely, treatment starts immediately without waiting for test results, which may take up to two days. Diagnostic tests focus on identifying the organism causing the illness. This may involve performing a culture on contaminated material from the suspect food or the nose or throat of the affected individual. In infant botulism, the infant's stool may be cultured to isolate the organism; this test may be performed by the state health department or the Centers for Disease Control (CDC). Culture results are available from the microbiology laboratory as soon as bacteria grow in a special plate incubated at temperatures at or above body temperature. The growth of Clostridium confirms the diagnosis. Sometimes the organism cultured is not Clostridium as suspected. The microbiology laboratory may use samples of the bacteria grown to perform other special techniques in order to help identify the causative organism.

While waiting for diagnostic test results, doctors ask about recently consumed food, possible open sores, recent activities and behavior, and other factors that may help to rule out other disease possibilities. A physical examination is done with an emphasis on the nervous system and muscle function. As part of this examination, imaging studies such as CT and MRI may be done and electrodiagnostic muscle function tests (electromyogram) or lumbar punctures may be ordered. Laboratory tests look for the presence of botulinum toxin or Clostridia in suspected foods and/or the child's blood serum, feces, or other specimens for traces of botulinum toxin or Clostridia. Magnesium levels may be measured, since magnesium increases the activity of Clostridium. Additional diagnostic tests may be done to rule out other diseases or conditions with similar symptoms.

Treatment

Drugs

Older children and adults with botulism are sometimes treated with an antitoxin derived from horse serum that is distributed by the Centers for Disease Control and Prevention. The antitoxin (effective against toxin types A, B, and E) inactivates only the botulinum toxin that is unattached to nerve endings. Early injection of the antitoxin, ideally within 24 hours of onset of symptoms, can preserve nerve endings, prevent progression of the disease, and reduce mortality.

Unfortunately, infants cannot receive the antitoxin used for adults. For them, human botulism immune globulin (BIG) is the preferred treatment. It is available in the United States through the Infant Botulism Treatment and Prevention Program in Berkeley, California. BIG neutralizes toxin types A, B, C, D, and E before they can bind to nerves. This antitoxin can provide protection against A and B toxins for approximately four months. Though many infants recover with supportive care, BIG cuts hospital stay in half and, therefore, reduces hospital costs by 50 percent as well.

Aside from the specific antitoxin, no therapeutic drugs are used to treat botulism. Antibiotics are not effective for preventing or treating botulism because the Clostridium group of toxins are not sensitive to them. In fact, antibiotic use is discouraged for infants because bacteria could potentially release more toxin into a baby's system as they are killed. Antibiotics can be used, however, to treat secondary respiratory tract and other infections.

Respiratory support

Treatment for infants usually requires them to be in an intensive care unit, involving intensive respiratory support and nasogastric tube feeding for weeks or even months. Once an infant can breathe unaided, physical therapy is initiated to help the child relearn how to suck and swallow. In older children and adults, a respirator is often required to assist breathing; a tracheostomy may be necessary in some cases.

Surgery

Surgery may be necessary to clean an infected wound (debridement) and remove the source of the bacteria producing the toxin. Antimicrobial therapy may be necessary.

Gastric lavage

When botulism in older children or adults is caused by food, it often is necessary to flush the gastrointestinal tract (gastric lavage). Often cathartic agents or enemas are used. It is important to avoid products that contain magnesium, since magnesium enhances the effect of the toxin.

Nutritional concerns

Parents should avoid feeding honey to infants younger than 12 months because it is one known source of botulism spores.

Prognosis

With medical intervention, botulism victims can recover completely, though it may be a very slow recovery. It takes weeks to months to recover from botulism, and
severe cases can take years before a total recovery is attained. Recovery depends on the nerve endings building new proteins to replace those destroyed by botulinum toxin.

Prevention

Vaccines have not been developed directed against botulism, which makes prevention of infant botulism or other forms of the disease difficult, since exposure to the botulinum toxic is typically unrecognized. Food safety is the surest prevention for botulism. Botulinum toxin cannot be seen, smelled, or tasted, so the wisest course is to discard any food that seems spoiled; avoid eating food from dented, rusty, or bulging cans; avoid refreezing meats once they have been thawed; and avoid buying broken containers of food or eating food that has been stored at room temperature or above for more than a few hours. People who like to can food at home must be diligent about using sterile equipment and following U.S. Department of Agriculture canning guidelines.

Infant botulism is difficult to prevent, because controlling what goes into an infant's mouth is often beyond control, especially in regard to airborne spores. One concrete preventative is to never feed honey to infants younger than 12 months as it is one known source of botulism spores. As infants begin eating solid foods, the same food precautions should be followed as for older children and adults.

Parental concerns

Because symptoms of infant botulism appear slowly, parents may be concerned that they will be missed or not found early. Normal watchfulness of the parents is sufficient, paying attention to any change in feeding, a decrease in bowel movements, or a lack of normal responses such
as turning of the head and body movements. It may be helpful to remember how rare botulism is, how easy it is to assure food safety, and also that morbidity and mortality can be avoided with early recognition of the symptoms.

KEY TERMS

Acetylcholine—A chemical called a neurotransmitter that functions primarily to mediate activity of the nervous system and skeletal muscles.

Antitoxin—An antibody against an exotoxin, usually derived from horse serum.

Computed tomography (CT)—An imaging technique in which cross-sectional x rays of the body are compiled to create a three-dimensional image of the body's internal structures; also called computed axial tomography.

Culture—A test in which a sample of body fluid is placed on materials specially formulated to grow microorganisms. A culture is used to learn what type of bacterium is causing infection.

Electrooculography (EOG)—A diagnostic test that records the electrical activity of the muscles that control eye movement.

Lumbar puncture—A procedure in which the doctor inserts a small needle into the spinal cavity in the lower back to withdraw spinal fluid for testing. Also known as a spinal tap.

Magnetic resonance imaging (MRI)—An imaging technique that uses a large circular magnet and radio waves to generate signals from atoms in the body. These signals are used to construct detailed images of internal body structures and organs, including the brain.

Neurotoxin—A poison that acts directly on the central nervous system.

Neurotransmitter—A chemical messenger that transmits an impulse from one nerve cell to the next.

Sepsis—A severe systemic infection in which bacteria have entered the bloodstream or body tissues.

Spore—A dormant form assumed by some bacteria, such as anthrax, that enable the bacterium to survive high temperatures, dryness, and lack of nourishment for long periods of time. Under proper conditions, the spore may revert to the actively multiplying form of the bacteria. Also refers to the small, thick-walled reproductive structure of a fungus.

Toxin—A poisonous substance usually produced by a microorganism or plant.

Tracheostomy—A procedure in which a small opening is made in the neck and into the trachea or windpipe. A breathing tube is then placed through this opening.

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Botulism

Gale Encyclopedia of Medicine, 3rd ed.
COPYRIGHT 2006 Thomson Gale

Botulism

Definition

Botulism is caused by botulinum toxin, a natural poison produced by certain bacteria in the Clostridium genus. Exposure to the botulinum toxin occurs mostly from eating contaminated food, or in infants, from certain clostridia growing in the intestine. Botulinum toxin blocks motor nerves' ability to release acetylcho-line, the neurotransmitter that relays nerve signals to muscles, and flaccid paralysis occurs. As botulism progresses, the muscles that control the airway and breathing fail.

Description

Botulism occurs rarely, but it causes concern because of its high fatality rate. Clinical descriptions of botulism possibly reach as far back in history as ancient Rome and Greece. However, the relationship between contaminated food and botulism wasn't defined until the late 1700s. In 1793 the German physician, Justinius Kerner, deduced that a substance in spoiled sausages, which he called wurstgift (German for sausage poison), caused botulism. The toxin's origin and identity remained elusive until Emile von Ermengem, a Belgian professor, isolated Clostridium botulinum in 1895 and identified it as the poison source.

Three types of botulism have been identified: foodborne, wound, and infant botulism. The main difference between types hinges on the route of exposure to the toxin. In the United States, there are approximately 110 cases of botulism reported annually. Food-borne botulism accounts for 25% of all botulism cases and usually can be traced to eating contaminated home-preserved food. Infant botulism accounts for 72% of all cases, but the recovery rate is good (about 98%) with proper treatment. From 1990 to 2000, 263 cases of food-borne cases were reported in the United States, most of them in Alaska. Though most were related to home canning, two restaurant-associated outbreaks affected 25 people.

Though domestic food poisoning is a problem world-wide, there has been a growing concern regarding the use of botulism toxin in biological warfare and terrorist acts. The Iraqi government admitted in 1995 that it had loaded 11,200 liters of botulinum toxin into SCUD missiles during the Gulf War. Luckily, these special missiles were never used. As of 1999, there were 17 countries known to be developing biological weapons, including the culture of botulism toxins.

Causes and symptoms

Toxin produced by the bacterium Clostridium botulinum is the main culprit in botulism. Other members of the clostridium genus can produce botulinum toxin, namely C. argentinense, C. butyricum, and C. baratii, but they are minor sources. To grow, these bacteria require a low-acid, oxygen-free environment that is warm (40-120°F or 4.4-48.8°C) and moist. Lacking these conditions, the bacteria transform themselves into spores that, like plant seeds, can remain dormant for years. Clostridia and their spores exist all over the world, especially in soil and aquatic sediments. They do not threaten human or animal health until the spores encounter an environment that favors growth. The spores then germinate, and the growing bacteria produce the deadly botulism toxin.

Scientists have discovered that clostridia can produce at least seven types of botulism toxin, identified as A, B, C, D, E, F, and G. Humans are usually affected by A, B, E, and very rarely F. Domesticated animals such as dogs, cattle, and mink are affected by botulism C toxin, which also affects birds and has caused massive die-offs in domestic bird flocks and wild waterfowl. Botulism D toxin can cause illness in cattle, and horses succumb to botulism A, B, and C toxin. There have been no confirmed human or animal botulism cases linked to the G toxin.

In humans, botulinum toxin latches onto specific proteins in nerve endings and irreversibly destroys them. These proteins control the release of acetylcholine, a neurotransmitter that stimulates muscle cells. With acetylcholine release blocked, nerves are not able to stimulate muscles. Ironically, botulinum toxin has found a beneficial niche in the world of medicine due to this action. Certain medical disorders are characterized by involuntary and uncontrollable muscle contractions. Medical researchers have discovered that injecting a strictly controlled dose of botulinum toxin into affected muscles inhibits excessive muscle contractions. The muscle is partially paralyzed and normal movement is retained. This is commonly referred to as Botox injection.

The three types of human botulism include the following symptoms:

Food-borne. Food that has been improperly preserved or stored can harbor botulinum toxin-producing clostridia. Botulism symptoms typically appear within 18-36 hours of eating contaminated food, with extremes of four hours to eight days. Initial symptoms include blurred or double vision and difficulty swallowing and speaking. Possible gastrointestinal problems include constipation, nausea, and vomiting. As botulism progresses, the victim experiences weakness or paralysis, starting with the head muscles and progressing down the body. Breathing becomes increasingly difficult. Without medical care, respiratory failure and death are very likely.

Infant. Infant botulism was first described in 1976. Unlike adults, infants younger than 12 months are vulnerable to C. botulinum colonizing the intestine. Infants ingest spores in honey or simply by swallowing spore-containing dust. The spores germinate in the large intestine and, as the bacteria grow, they produce botulinum toxin that is absorbed into the infant's body. The first symptoms include constipation, lethargy, and poor feeding. As infant botulism progresses, sucking and swallowing (thus eating) become difficult. A nursing mother will often notice breast engorgement as the first sign of her infant's illness. The baby suffers overall weakness and cannot control head movements. Because of the flaccid paralysis of the muscles, the baby appears "floppy." Breathing is impaired, and death from respiratory failure is a very real danger.

Wound. Confirmed cases of wound botulism have been linked to trauma such as severe crush injuries to the extremities, surgery, and illegal drug use. Wound botulism occurs when clostridia colonize an infected wound and produce botulinum toxin. The symptoms usually appear four to 18 days after an injury occurs and are similar to food-borne botulism, although gastrointestinal symptoms may be absent.

KEY TERMS

Acetylcholine— A chemical released by nerve cells to signal other cells.

Antitoxin— A substance that inactivates a poison (e.g., toxin) and protects the body from being injured by it.

CT scan— The abbreviated term for computed or computerized axial tomography. The test may involve injecting a radioactive contrast into the body. Computers are used to scan for radiation and create cross-sectional images of internal organs.

Electromyographic test— A medical test which determines if a muscle's response to electrical stimuli. The test results allow medical personnel to assess how nerves to the muscle are functioning.

Lumbar puncture— A procedure in which a small amount of cerebrospinal fluid is removed from the lower spine. Examination of this fluid helps diagnose certain illnesses.

MRI— The abbreviated term for magnetic resonance imaging. MRI uses a large circular magnet and radio waves to generate signals from atoms in the body. These signals are used to construct images of internal structures.

Neurotransmitter— A chemical found in nerves that relays nerve signals to other cells. Acetylcholine is a neurotransmitter.

Sepsis— The presence of infection-causing organisms or associated toxins in the blood or within body tissues.

Spores— A state of "suspended animation" that some bacteria can adopt when conditions are not ideal for growth. Spores are analogous to plant seeds and can germinate into growing bacteria when conditions are right.

Toxin— A poisonous substance produced by a microorganism, plant, or animal.

Tracheostomy— The procedure used to open a hole in the neck to the trachea, or windpipe. It is sometimes used in conjunction with a respirator.

Diagnosis

Diagnosis of botulism can be tricky because symptoms mimic those presented by other diseases. Botulism may be confused with Guillain-Barre syndrome, myasthenia gravis, drug reactions, stroke, or nervous system infection, intoxications (e.g. carbon monoxide or atropine), or shellfish poisoning. Sepsis is the most common initial diagnosis for infant botulism. Failure to thrive may also be suspected. Some reports have linked infant botulism to 5-15% of sudden infant death syndrome (SIDS, crib death) cases. Laboratory tests are used for definitive diagnosis, but if botulism seems likely, treatment starts immediately.

While waiting for laboratory results, doctors ask about recently consumed food and work to dismiss other disease possibilities. A physical examination is done with an emphasis on the nervous system. As part of this examination, CT scans, MRIs, electromyographic tests, or lumbar punctures may be ordered. Laboratory tests involve testing a suspected food and/ or the patient's serum, feces, or other specimens for traces of botulinum toxin or clostridia.

Treatment

Drugs

Adults with botulism are treated with an antitoxin derived from horse serum that is distributed by the Centers for Disease Control and Prevention. The antitoxin (effective against toxin types A, B, and E) inactivates only the botulinum toxin that is unattached to nerve endings. Early injection of antitoxin (usually within 24 hours of onset of symptoms) can preserve nerve endings, prevent progression of the disease, and reduce mortality.

Infants, however, cannot receive the antitoxin used for adults. For them, human botulism immune globulin (BIG) is available in the United States through the Infant Botulism Treatment and Prevention Program in Berkeley, California. BIG neutralizes toxin types A, B, C, D, and E before they can bind to nerves. This antitoxin can provide protection against A and B toxins for approximately four months. Though many infants recover with supportive care, BIG cuts hospital stay in half, and therefore reduces hospital costs by 50% as well.

Aside from antitoxin, no drugs are used to treat botulism. Antibiotics are not effective for preventing or treating botulism. In fact, antibiotic use is discouraged for infants because dying bacteria could potentially release more toxin into a baby's system. Antibiotics can be used, however, to treat secondary respiratory tract and other infections.

Respiratory support

Treatment for infants usually involves intensive respiratory support and tube feeding for weeks or even months. Once an infant can breathe unaided, physical therapy is initiated to help the child relearn how to suck and swallow. A respirator is often required to help adult patients breathe, and a tracheostomy may also be necessary.

Surgery

Surgery may be necessary to clean an infected wound and remove the source of the bacteria that is producing the toxin. Antimicrobial therapy may be necessary.

Gastric lavage

When botulism is caused by food, it often is necessary to flush the gastrointestinal tract (gastric lavage). Often cathartic agents or enemas are used. It is important to avoid products that contain magnesium, since magnesium enhances the effect of the toxin.

Prognosis

With medical intervention, botulism victims can recover completely, though slowly. It takes weeks to months to recover from botulism, and severe cases can take years before a total recovery is attained. Recovery depends on the nerve endings building new proteins to replace those destroyed by botulinum toxin.

Prevention

Vaccines against botulism do not exist to prevent infant botulism or other forms of the disease. However, scientists announced in 2004 that they had successfully vaccinated mice and ducks against type C and D, which may help lead to vaccines for humans. Food safety is the surest prevention for botulism. Botulinum toxin cannot be seen, smelled, or tasted, so the wisest course is to discard any food that seems spoiled without tasting it. Home canners must be diligent about using sterile equipment and following U.S. Department of Agriculture canning guidelines. If any part of a canned food container is rusty or bulging, the food should not be eaten. Infant botulism is difficult to prevent, because controlling what goes into an infant's mouth is often beyond control, especially in regard to spores in the air. One concrete preventive is to never feed honey to infants younger than 12 months since it is one known source of botulism spores. As infants begin eating solid foods, the same food precautions should be followed as for adults.

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In addition to the MLA, Chicago, and APA styles, your school, university, publication, or institution may have its own requirements for citations. Therefore, be sure to refer to those guidelines when editing your bibliography or works cited list.

Botulism

Botulism

Definition

Botulism is a neuroparalytic disease caused by the potent toxin of the Clostridium botulinum bacterium. There are three main types of botulism: foodborne botulism, infant botulism, and wound botulism.

Description

Botulism was first identified in Wildbad, Germany, in 1793, when six people died after consuming a locally produced blood sausage. In 1829, Jutinius Kerner, a health official, described 230 cases of sausage poisoning. Thereafter, the illness became known as "botulism," which is derived from the Latin "botulus," meaning sausage. In 1897, E. Van Ermengem identified the bacterium and its toxin while investigating an outbreak of the disease among musicians in Elezells, Belgium.

C. botulinum is a spore-forming, anaerobic, grampositive bacilli found globally in soil and honey. The toxin has recently gain notoriety. It is a potential bioterrorism agent, and it is used as a beauty aid to eliminate frown lines.

Clinically, food-borne botulism is dominated by neurological symptoms, including dry mouth, blurred vision and diplopia, caused by the blockade of neuromuscular junctions.

In wound botulism the neurologic findings are similar to the food-borne illness, but the gastrointestinal symptoms are absent. Infants suffering from the intestinal colonization of spores of C. botulinum suffer first from constipation, and later develop neurological paralysis, which can lead to respiratory distress.

There are seven distinct neurotoxic serotypes, all of which are closely related to the tetanus toxin. Types A and B are most commonly implicated, but types E and, more rarely, F have been associated with human disease.

Demographics

Botulism is rare, but its incidence does vary by geographic region. The food-borne version remains highest among people who can their own foods. In 1995, only 24 cases of food-borne botulism were reported to the Centers for Disease Control and Prevention.

About 90% of global cases of infant botulism are diagnosed in the US, where the annual incidence is about 2 per 100,000 live births. It is the most common form of human botulism in the United States, with over 1,400 cases diagnosed between 1976 and 1996.

Between 1943 and 1985, 33 cases of wound botulism were diagnosed in the United States, mainly associated with deep and avascular wounds. However, between 1986 and 1996, 78 cases of wound botulism were diagnosed, many the result of illicit drug use, occurring at injection sites or at nasal or sinus sites associated with chronic cocaine snorting.

Causes and symptoms

Botulism is caused by the protein toxin released by the microorganism C. botulinum. After the toxin is absorbed into the bloodstream, it irreversibly binds to the acetylcholine receptors on the motor nerve terminals at neuromuscular junctions. After the toxin is internalized, it cleaves the apparatus in the neuron that is responsible for acetylcholine release, making the neuron unresponsive to action potentials. The blockade is irreversible and may last for months, until new nerve buds grow.

FOOD-BORNE BOTULISM The symptoms can range from mild to life threatening, depending on the toxin dose. Generally, symptoms appear within 36 hours of consuming food containing the toxin. Paralysis is symmetric and descending. The first symptoms to appear include dysphagia, dysarthria , and diplopia, a reflection of cranial nerve involvement. Neck and limb weakness, nausea, vomiting, and dizziness follow. Respiratory muscle paralysis can lead to ventilatory failure and death unless support is provided.

WOUND BOTULISM The in vivo production of toxin by C. botulinum spores, leads to the neurologic symptoms seen in food-borne botulism. Gastrointestinal symptoms are absent.

INFANT BOTULISM Peak incidence occurs between 2 and 3 months of age. C. botulinum spores colonize the gastrointestinal tract and produce the toxin. Most infants show signs of constipation, followed by neuromuscular weakness that results in decreased sucking, lack of muscle tone and characteristic "floppy head." Symptoms may range from mild to severe, and may lead to respiratory failure.

Diagnosis

Physicians should consider a diagnosis of botulism in a patient who presents with neuromuscular impairment, but remains mentally alert. The disease is often mistaken for other more common conditions, including stroke , encephalitis, Guillain-Barré syndrome, myasthenia gravis , tick paralysis, chemical or mushroom poisoning, and adverse reactions to antibiotics or other medication. Sepsis, electrolyte imbalances, Reye syndrome , congenital myopathy , Werdnig-Hoffman disease and Leigh disease should be considered in infants.

A definitive diagnosis can be made by detecting the toxin in serum samples, or isolating C. botulinum from stool or wound specimens. Toxins can be detected with a mouse neutralization assay, or using PCR or ELISA protocols.

Treatment

Because of the threat of respiratory complications, patients should be hospitalized immediately and closely monitored. Mechanical ventilation should begin when the vital capacity falls below 30% of predicted. Trivalent (types A, B and E) equine antitoxin should be administered as soon as botulism is suspected to slow the progression of the illness and limit the duration of respiratory failure in critical cases. Caution should be exercised as approximately 9% of patients experience a hypersensitivity reaction. Due to the high incidence of side effects and anaphylaxis, infants should not receive equine antitoxin.

In 2003, the FDA approved an intravenously administered human botulism immune globulin for types A and B infant botulism.

Patients suffering from wound botulism should receive equine antitoxin and antibiotics such as penicillin.

Clinical Trials

As of early 2004, there was one open clinical trial for infant botulism at the National Institutes of Health (NIH), to assess the safety and efficacy of human botulism immune globulin.

Prognosis

Prompt diagnosis and treatment coupled with improved respiratory care have decreased mortality from food-borne botulism. Severe cases often call for prolonged respiratory support. The case-fatality rate is 7.5%, although mortality is greater in patients older than 60 years. Infant botulism has an excellent prognosis, although relapse can occur following hospital discharge. The case-fatality rate for infant botulism is 2%. Because toxin binding is irreversible, acetylocholine release and strength return only after the nerve terminals sprout new endings.

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Botulism

World of Microbiology and Immunology
COPYRIGHT 2003 The Gale Group Inc.

Botulism

Botulism is an illness produced by a toxin that is released by the soil bacterium Clostridium botulinum. One type of toxin is also produced by Clostridium baratii. The toxins affect nerves and can produce paralysis. The paralysis can affect the functioning of organs and tissues that are vital to life.

There are three main kinds of botulism. The first is conveyed by food containing the botulism toxin. Contaminated food can produce the illness after being ingested. Growth of the bacteria in the food may occur, but is not necessary for botulism. Just the presence of the toxin is sufficient. Thus, this form of botulism is a food intoxication (as compared with food poisoning, where bacterial growth is necessary). The second way that botulism can be produced is via infection of an open wound with Clostridium botulinum. Growth of the bacteria in the wound leads to the production of the toxin, which can diffuse into the bloodstream. The wound mode of toxin entry is commonly found in intravenous drug abusers. Finally, botulism can occur in young children following the consumption
of the organism, typically when hands dirty from outdoor play are put into the mouth.

The latter means of acquiring botulism involves the form of the bacterium known as a spore. A spore is a biologically dormant but environmentally resilient casing around the bacterium's genetic material. The spore form allows the organism to survive through prolonged periods of inhospitable conditions. When conditions improve, such as when a spore in soil is ingested, resuscitation, growth of the bacterium, and toxin production can resume. For example, foodborne botulism is associated with canned foods where the food was not heated sufficiently prior to canning to kill the spores.

Botulism is relatively rare. In the United States, just over 100 cases are reported each year, on average. The number of cases of foodborne and infant botulism has not changed appreciably through the 1990s to the present day. Foodborne cases have tended to involve the improper preparation of home-canned foods.

There are seven known types of botulism toxin, based on their antigenic make-up. These are designated toxins A through G. Of these, only types A, B, E, and F typically cause botulism in humans, although involvement of type C toxin in infants has been reported, and may be particularly associated with the consumption of contaminated honey.

Infant botulism caused by toxin type C may be different from the other types of botulism in that the toxin is produced in the person following the ingestion of living Clostridium botulinum.

The toxins share similarities in their gross structure and in their mechanism of action. The toxins act by binding to the region of nerve cells that is involved in the release of a chemical known as a neurotransmitter. Neurotransmitters travel across the gap (synapse) separating neurons (nerve cells) and are essential to the continued propagation of a neural impulse. Accordingly, they are vital in maintaining the flow of a transmitted signal from nerve to nerve. Blocking nerve transmissions inhibits the means by which the body can initiate the movement of muscles. The result is paralysis. This paralysis produces a variety of symptoms including double or blurred vision, drooping eyelids, slurred speech, difficulties in swallowing, muscle weakness, paralysis of limbs and respiratory muscles.

The appearance of the symptoms of botulism vary depending on the route of toxin entry. For example, ingestion of toxin-contaminated food usually leads to symptoms within two to three days. However, symptoms can appear sooner or later depending on whether the quantity of toxin ingested is low or high.

The diagnosis of botulism and so the start of the appropriate therapy can be delayed, due to the relative infrequency of the malady and its similarity (in the early stages) with other maladies, such as Guillain-Barré syndrome and stroke. Diagnosis can involve the detection of toxin in the patient's serum, isolation of living bacteria from the feces, or by the ability of the patient's sample to produce botulism when introduced into test animals.

Clostridium botulinum requires an oxygen-free atmosphere to grow. Growth of the bacteria is associated with the production of gas. Thus, canned foods can display a bulging lid, due to the build-up of internal pressure. Recognition of this phenomenon and discarding of the unopened can is always a safe preventative measure.

Studies conducted by United States health authorities have shown that the different forms of the botulism toxin display some differences in their symptomatology and geographic distribution. Type A associated botulism is most prevalent in the western regions of the US, particularly in the Rocky Mountains. This toxin produces the most severe and long-lasting paralysis. Type B toxin is more common in the eastern regions of the country, especially in the Allegheny mountain range. The paralysis produced by type B toxin is less severe than with type A toxin. Type E botulism toxin is found more in the sediments of fresh water bodies, such as the Great Lakes. Finally, type F is distinctive as it is produced by Clostridium baratii.

Treatment for botulism often involves the administration of an antitoxin, which acts to block the binding of the toxin to the nerve cells. With time, paralysis fades. However, recovery can take a long time. If botulism is suspected soon after exposure to the bacteria, the stomach contents can be pumped out to remove the toxic bacteria, or the wound can be cleaned and disinfected. In cases of respiratory involvement, the patient may need mechanical assistance with breathing until lung function is restored. These measures have reduced the death rate from botulism to 8% from 50% over the past half century.

As dangerous as botulinum toxin is when ingested or when present in the bloodstream, the use of the toxin has been a boon to those seeking non-surgical removal of wrinkles. Intramuscular injection of the so-called "Botox" relaxes muscles and so relieves wrinkles. Thus far, no ill effects of the cosmetic enhancement have appeared. As well, Botox may offer relief to those suffering from the spastic muscle contractions that are a hallmark of cerebral palsy.

See also Bacteria and bacterial diseases; Bioterrorism; Food safety

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Botulinum Toxin

Botulinum toxin

Definition

Botulinum toxin is the purified form of a poison created by the bacterium Clostridium botulinum. These bacteria grow in improperly canned food and cause botulism poisoning. Minute amounts of the purified form can be injected into muscles to prevent them from contracting; it is used in this way to treat a wide variety of disorders and cosmetic conditions.

Purpose

Botulinum toxin was developed to treat strabismus (cross-eye or lazy eye), and was shortly thereafter discovered to be highly effective for many forms of dystonia . Spasticity can also be effectively treated with botulinum toxin. Injected into selected small muscles of the face, it can reduce wrinkling. Other conditions treated with botulinum toxin include:

achalasia

anismus

back pain

bruxism

excess saliva production

eyelid spasm

headache

hemifacial spasm

hyperhidrosis

migraine

palatal myoclonus

spastic bladder

stuttering

tics

tremor

uncontrollable eye blinking

vaginismus

It is important to note that as of early 2004, the only Food and Drug Administration-approved uses for botulinum toxin are for certain forms of dystonia, hemifacial spasm, strabismus, blepharospasm (eyelid spasms), and certain types of facial wrinkles. While there is general recognition that certain other conditions can be effectively treated with botulinum toxin, other uses, including for headache or migraine, are considered experimental.

Description

A solution of botulinum toxin is injected into the overactive muscle. The toxin is taken up by nerve endings at the junction between nerve and muscle. Once inside the cell, the toxin divides a protein. The normal job of this protein is to help the nerve release a chemical, a neurotransmitter, which stimulates the muscle to contract. When botulinum toxin divides the protein, the nerve cannot release the neurotransmitter, and the muscle cannot contract as forcefully.

The effects of botulinum toxin begin to be felt several days after the injection. They reach their peak usually within two weeks, and then gradually fade over the next 2–3 months. Since the effects of the toxin disappear after several months, reinjection is necessary for continued muscle relaxation.

Recommended dosage

In the United States, purified botulinum toxin is available in two commercial forms: Botox and MyoBloc. The recommended doses of the two products are quite different, owing to the differing potencies of the two products. The size of the muscle and the degree of weakening desired also affect the dose injected. For Botox, the maximum recommended dose for adults is 400–600 units in any three-month period, while for MyoBloc it is 10,000–15,000 units. The maximum dosage may be reached in the treatment of spasticity or cervical dystonia, while much smaller amounts are used in the treatment of facial lines, strabismus, and hemifacial spasm.

Precautions

When injected by a trained physician, botulinum toxin is very safe. The toxin remains mainly in the muscle injected, spreading only slightly to surrounding muscles or beyond. Botulism poisoning, which occurs after ingesting large amounts of the toxin, is due to the effects of the poison on the breathing muscles. In medical use, far less toxin is injected, and care is taken to avoid any chance of spread to muscles needed for breathing. Injection into the shoulders or neck may weaken muscles used for swallowing, which patients need to be aware of. Some patients may need to change to a softer diet to make swallowing easier during the peak effect of their treatment.

Repeated injections of large amounts of botulinum toxin can lead to immune system resistance. While this is not a dangerous condition, it makes further treatment ineffective.

Patients with neuromuscular disease should not receive treatment with botulinum toxin without careful consultation with a neurologist familiar with its effects.

Side effects

Botulinum toxin can cause a mild flu-like syndrome for several days after injection. Injection of too much toxin causes excess weakness, which may make it difficult to carry on normal activities of daily living. In some patients, toxin injection may cause blurred vision and dry mouth. This is more common in patients receiving MyoBloc than with Botox.

Interactions

Patients taking aminoglycoside antibiotics may be cautioned against treatment with botulinum toxin. These antibiotics include gentamicin, kanamycin, and tobramycin, among others.

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Botulinum Toxin

Encyclopedia of Espionage, Intelligence, and Security
COPYRIGHT 2004 The Gale Group Inc.

Botulinum Toxin

█ BRIAN HOYLE

Botulinum toxin is among the most poisonous substances known. The toxin, which can be ingested or inhaled, and which disrupts transmission of nerve impulses to muscles, is naturally produced by the bacterium Clostridium botulinum. Certain strains of C. baratii and C. butyricum can also be capable of producing the toxin.

Botulinum toxin has become well known in recent years for two reasons. First, the toxin has become a weapon in the arsenal of terrorists. Contamination of food is one route for infection with the toxin. The toxin can also be released into the air, which was attempted on at least three occasions between 1990 and 1995 by the Japanese cult Aum Shinrikyo. The government of Iraq admitted to United Nations inspectors following the 1991 Persian Gulf War that tens of thousands of liters of botulism toxin had been produced and loaded into weapons. The toxin was the most numerous of all the biological weapons then developed by Iraq.

Paradoxically, the other reason for the toxin's fame is the use of the toxin as a cosmetic enhancement (i.e., "botox").

There are at least seven structurally different versions of botulinum toxin. The type designated as type A is responsible for some food-borne outbreaks in the United States and elsewhere. Improperly canned foods are a particular threat.

Clostridium botulinum is a spore-forming bacterium. Like the well-known anthrax bacillus, the spores of Clostridium botulinum can persist in the environment for many years and, when conditions become more favorable (i.e., in a wound, food, and the lungs) the spore can germinate and free the toxin. Dried preparations of the spores can thus represent a terrorist weapon.

The use of botulinum toxin as a weapon began in the 1930s, with experiments conducted by the Japanese on prisoners during the occupation of Manchuria. In World War II, plans were made to vaccinate Allied troops participating in the D-day invasion of Normandy, because of concerns that Germany had weaponized the toxin. Even the United States maintained an active biological weapons program, including the use of botulism toxin, into the late 1960s.

Botulism toxin acts by preventing the transmission of nerve signals between the nerves that connect with muscle cells. Progressive functional deterioration of the affected muscles occurs. Symptoms of botulism intoxication include dizziness, blurred or double vision, nausea, vomiting, diarrhea, and weakness of muscles in various areas of the body. The muscle failure can be so severe as to lead to coma and respiratory arrest. Even in those who survive exposure to the toxin, complete recovery can take months.

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Botulism

Encyclopedia of Food and Culture
COPYRIGHT 2003 The Gale Group Inc.

BOTULISM

BOTULISM. Botulism is a paralytic illness caused by a nerve toxin produced by the soil bacterium Clostridium botulinum and spread by contaminated food or by infection of a wound. The term comes from the Latin botulus (sausage), but the vehicle in food-borne cases today is usually vegetables or other food improperly canned at home. Commercial canning is almost never implicated, although a notable case in 1971 left one person dead and several others seriously injured. The illness is rare, with only twenty-five to thirty food-borne cases reported annually in the United States.

C. botulinum is a spore-forming bacteria that can lie dormant in the soil for months or years. In a warm, moist, low-oxygen environment, however, the spores can produce vegetative cells that multiply rapidly and secrete a deadly toxin, which attacks the nervous system of the person ingesting contaminated food.

Symptoms of botulism include double vision, blurred vision, drooping eyelids, slurred speech, difficulty in swallowing, dry mouth, and muscle weakness. An antitoxin can be used with early diagnosis, but otherwise treatment involves supportive care, sometimes including a ventilator. A severe case can require months of medical and nursing care and may leave the patient with permanent impairments. Botulism is fatal in about 8 percent of cases, usually from respiratory failure.

Thorough washing can remove the spores and proper heating will destroy them. If, however, the food being canned is not washed properly and fails to reach the necessary temperature for the required time, the spores can germinate and produce toxin in the canned goods.

A pH in the acid range will also kill the spores, so acidic foods such as fruit and tomatoes are less likely to be vehicles than low-acid food such as corn, green beans, or asparagus. Canners are often advised to raise the acidity of food by adding an acid source such as lemon juice or citric acid.

To avoid the danger of botulism, home canners of low-acid foods are advised to use a pressure canner instead of the unpressurized, boiling-water-bath systems used previously. A temperature of up to 250°F is needed, which can be reached with pressure canners operated at ten to fifteen pounds per square inch. The time required ranges from twenty to one hundred minutes, depending on the food and the size of the jars. Detailed instructions are available with home canning systems, either from the U.S. Department of Agriculture or from an extension agent.

Industrial quality control makes it highly unlikely that commercially canned food will be contaminated with botulinum toxin. However, consumers should reject any commercial canned goods that appear swollen or bulging and any canned food with a bad smell or flavor.

In recent years, scientists have recognized an infant form of botulism in which infants ingest spores that germinate and produce toxins in the intestines. This appears to be linked mainly to the ingestion of raw honey, so authorities urge parents never to feed raw honey to babies. There is little danger of this variant of the disease after the age of one year.

See also Packaging and Canning, History of ; Packaging and Canning, Modern ; Safety, Food .

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Botulinum Toxin

World of Forensic Science
COPYRIGHT 2005 Thomson Gale

Botulinum Toxin

Clostridium botulinum is a spore-forming bacterium. Like the well-known anthrax bacillus, the spores of Clostridium botulinum can persist in the environment for many years and, when conditions become more favorable (i.e., in a wound, food, and the lungs) the spore can germinate and free the toxin.

There are at least seven structurally different versions of botulinum toxin. The type designated as type A is responsible for some botulism food-borne outbreaks in the United States and elsewhere. Improperly canned foods are a particular threat.

Botulinum toxin is among the most poisonous substances known in the natural world. The toxin, which can be ingested or inhaled, and which disrupts transmission of nerve impulses to muscles, is naturally produced by the bacterium Clostridium botulinum. Certain strains of C. baratii and C. butyricum can also be capable of producing the toxin.

Botulinum toxin acts by preventing the transmission of nerve signals between the nerves that connect with muscle cells. Progressive functional deterioration of the affected muscles occurs. Symptoms of botulism intoxication include dizziness, blurred or double vision, nausea, vomiting, diarrhea, and weakness of muscles in various areas of the body. The muscle failure can be so severe as to lead to coma and respiratory arrest. Even in those who survive exposure to the toxin, complete recovery can take months.

The damage and lethality that can be inflicted by the toxin makes this agent important in forensic science . If botulism toxin poisoning is suspected, a
forensic scientist can check for the presence of the bacterial spores.

The sometimes deliberate use of the toxin is also forensically relevant. Contamination of food is one route for infection with the toxin. This can occur naturally, via the bacterial contamination of the food. On the other hand, food can be deliberately contaminated. As well, the toxin can also be released into the air. The latter is invariably deliberate. For example, on at least three occasions between 1990 and 1995, while experimenting with biological warfare agents, the Japanese cult Aum Shinrikyo released botulinum toxins , but failed in attempts to spread them.

see also Biodetectors; Bioterrorism; Nervous system overview; Pathogens; Toxins.

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Botulism

Encyclopedia of Public Health
COPYRIGHT 2002 The Gale Group Inc.

BOTULISM

Botulism is a rare disease that occurs in four forms: food-borne botulism (the most common form); infant botulism (sometimes associated with honey); an adult form of infant botulism; and wound infection botulism. Botulism is caused by botulinum neurotoxin, which blocks acetylcholine release at neuromuscular junctions, resulting in paralysis. The toxin is produced under anaerobic conditions by Clostridium botulinum, a bacterium found widely in the environment.

In food-borne botulism, the preformed toxin is ingested. There are two main bacterial strains: Group I strains are proteolytic, have spores that are highly resistant to heat, and cannot grow below 10°C. Group II strains are nonproteolytic, are less likely to survive thermal processing or grow in acid or salty products, and grow at refrigeration temperatures. The canning industry has developed retort conditions to prevent the survival of all spores.

Symptoms of food-borne botulism include double vision, inability to speak or swallow, labored breathing, and death. Food-borne botulism can be caused by improperly processed or stored foods, including vegetables, meat, fish, and cheese. The annual incidence of botulism is highest in Russia, Poland, and Hungary with 0.2 to 0.3 cases per 100,000 persons (due to contaminated home-preserved foods); and in the Innuit populations of Canada and Alaska (60 cases per 100,000 persons in northern Quebec), where it is usually associated with toxins in putrefied whale, seal, or fish products.

Symptoms of infant botulism include constipation, weakness, and respiratory arrests, but rarely death.

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botulism

The Columbia Encyclopedia, 6th ed.

Copyright The Columbia University Press

botulism (bŏch´əlĬz´əm), acute poisoning resulting from ingestion of food containing toxins produced by the bacillus Clostridium botulinum. The bacterium can grow only in an anaerobic atmosphere, such as that found in canned foods. Consequently, botulism is almost always caused by preserved foods that have been improperly processed, usually a product canned imperfectly at home. The toxins are destroyed by boiling canned food for 30 min at 176°F (80°C). Once the toxins (which are impervious to destruction by the enzymes of the gastrointestinal tract) have entered the body, they interfere with the transmission of nerve impulses, causing disturbances in vision, speech, and swallowing, and ultimately paralysis of the respiratory muscles, leading to suffocation. Symptoms of the disease appear about 18 to 36 hr after ingestion of toxins. Botulinus antiserum is given to persons who have been exposed to contaminated food before they develop symptoms of the disease and is given to diagnosed cases of the disease as soon as possible. Developments in early detection have reduced the mortality rate from 65% to 10%.

In a technique pioneered by Alan B. Scott, an ophthalmologist, and Edward Schantz, a biochemist, in the late 1970s, botulin toxin has been purified and used in the treatment of debilitating muscle spasms caused by the excessive firing of certain nerves. The treatment utilizes the same process that paralyzes the muscles in botulism poisoning. Injected in tiny amounts into the affected tissue, the botulin blocks the release of acetylcholine, a neurotransmitter that controls muscle contraction, and temporarily relieves the spasms. Botulin was approved by the Food and Drug Administration in 1989 for treatment of blepharospasm (uncontrolled rapid blinking) and strabismus (crossed eyes). The toxin is also injected to treat other conditions, such as neck muscle spasms, and to provide short-term (three to four months) cosmetic treatment of facial wrinkles.

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botulism

botulism A rare form of food poisoning caused by the extremely potent neurotoxins produced by Clostridium botulinum (isolated in 1895 by Belgian bacteriologist Emilie Pierre‐Marie van Ermengem). At least seven different toxins have been identified; they can be inactivated by heating at 80 °C for 10 min., but in foods are more resistant to heat. Although rare, it is often fatal unless the antitoxin is given.

The name is derived from botulus, for sausage, since the disease was originally associated with sausages in Germany (the first recorded outbreak was in 1735). A wide range of foods have been involved, including meat, fish, milk, fruits, and vegetables which have been incorrectly preserved or treated, so that competing micro‐organisms have been destroyed; spores of C. botulinum are extremely resistant to heat, and dangerous amounts of toxins can accumulate in contaminated foods without any apparent spoilage.

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There are seven types of botulinum toxin, each designated by a letter from A through G. Only four types (A, B, E, and F) make people sick. There are three forms of naturally occurring human botulism: infant botulism, food-borne botulism, and wound botulism. Inhalation (in-huh-LAY-shun) botulism is an additional form of the illness that could possibly be spread through the air intentionally by man. Clostridium botulinum is commonly found in soil and grows best in low-oxygen environments. The bacteria form spores* that remain dormant, or inactive, waiting for conditions that allow them to grow. The spores can exist everywhere, and people might eat food containing these spores without becoming sick. When conditions are right, however, the spores can activate and produce toxin.

are a temporarily inactive form of a germ enclosed in a protective shell.

Food contaminated with the toxin is the culprit in cases of food-borne botulism; most outbreaks stem from food that is improperly cooked or incorrectly canned or preserved. In food-borne botulism the toxin itself is swallowed, but in cases of infant botulism an infant swallows the spores and they then activate in the intestine and produce toxin. It is believed that the infant intestine lacks enough protective intestinal bacteria, stomach acid, and immune globulins* to prevent the spores from activating. Wound botulism is rare and develops when bacteria infect a wound and grow, producing the toxin. Bioterrorists have attempted to aerosolize* botulinum toxin without success, but the threat of inhalation botulism as a biological weapon has raised concerns.

More than 100 cases of botulism are reported in the United States each year. Infant botulism accounts for about 72 percent of reported cases and food-borne botulism for about 25 percent. Wound botulism is the rarest form, but health officials have noted an increase in this type in California, a rise they attribute to the intravenous* use of illegal drugs from Mexico.

(in-tra-VEE-nus) means within or through a vein. For example, medications, fluid, or other substances can be given through a needle or soft tube inserted through the skin’s surface directly into a vein.

Botulism is not contagious. Outbreaks of food-borne botulism usually can be traced to improperly home-canned foods, especially those with low amounts of acid, such as asparagus, green beans, beets, and corn, which allow the Clostridium botulinum bacteria to grow. Various frozen foods also have been implicated in outbreaks of the disease. Most infants contract botulism by inhaling or swallowing spores; honey is one source of these spores. Wound botulism sometimes is linked to crush injuries.

The classic symptoms of botulism include blurred or double vision*, droopy eyelids, slurred speech, difficulty in swallowing, dry mouth, and muscle weakness. These symptoms appear when the toxin interrupts nerve impulses to the muscles, which paralyzes the muscles. If untreated, paralysis may progress to involve the arms, legs, trunk, and muscles of the respiratory tract*. In food-borne botulism, symptoms generally begin 18 to 36 hours after eating the contaminated food, but they can occur after as little as 6 hours or as much as 10 days. Infants with botulism may appear drowsy or sluggish, not eat well, be constipated, and have a weak cry and muscle weakness. In infants, it can take 3 to 30 days for the symptoms to appear and progress.

Laboratory tests can detect the toxin in blood, stool (bowel movements), or wound samples. Because the symptoms of botulism are similar to those of stroke* and several other nerve diseases, doctors also may order a brain scan, spinal tap*, or other nerve- and muscle-function tests to check for other possible causes. The doctor may ask whether the patient has eaten any home-canned foods and, if so, order tests on the suspect food.

is a brain-damaging event usually caused by interference with blood flow to the brain. A stroke may occur when a blood vessel supplying the brain becomes clogged or bursts, depriving brain tissue of oxygen. As a result, nerve cells in the affected area of the brain, and the specific body parts they control, do not properly function.

also called a lumbar puncture, is a medical procedure in which a needle is used to withdraw a sample of the fluid surrounding the spinal cord and brain. The fluid is then tested, usually to detect signs of infection, such as meningitis, or other diseases.

The U.S. Centers for Disease Control and Prevention (CDC) has a supply of antitoxin* against botulism. The antitoxin can slow or halt the damage caused by botulinum toxin. The sooner it is given, the more effective it is in easing the symptoms. To help rid the body of the toxin, doctors sometimes cause vomiting or use enemas*. In severe cases, patients who are unable to breathe well enough on their own might need a ventilator (VEN-tuh-lay-ter), a machine that can help a person breathe for several weeks. Wound botulism might require surgery to remove the source of the toxin-producing bacteria.

Most people with botulism require hospitalization, but they typically recover after weeks or perhaps months of care. Paralysis of the respiratory muscles can lead to pneumonia*. Even after recovery, some patients may be tired and feel short of breath.

Although botulinum toxin is extremely potent, it can be destroyed easily. Heating food and drinks to an internal temperature of 185 degrees Fahrenheit for at least 5 minutes will detoxify them. Boiling home-canned foods before eating them also lessens risk. Health officials advise using a pressure cooker and high temperatures—about 250 degrees Fahrenheit—to kill the spores when canning or preserving foods at home. It also is best to avoid eating commercially prepared foods from cans that are swollen, punctured, or leaking. Because honey can contain spores of Clostridium botulinum, doctors advise that infants younger than 1 year not be given this sweetener. Breast-feeding can help protect against infant botulism. Receiving prompt medical care for infected wounds and not injecting street drugs can help prevent wound botulism.

Clostridium botulinum bacteria as seen with an electron microscope. Visuals Unlimited

Website

KidsHealth.org. KidsHealth is a website created by the medical experts of the Nemours Foundation and is devoted to issues of children’s health. It contains articles on a variety of health topics, including botulism. http://www.KidsHealth.org

For Good and Evil

Botulinum toxin is the first biological toxin licensed for treatment of human diseases. The U.S. government approves its use to relax painfully cramped or tight muscles and as an ingredient in medications for the treatment of migraine headache, chronic lower back pain, stroke, brain injury, and cerebral palsy. Botulinum toxin injections (called Botox) can paralyze muscles that cause the skin to wrinkle. Their use is popular among people looking to maintain a youthful appearance.

Ironically, the same substance has the potential to cause mass destruction if it is dispersed into the air or introduced into the food supply. The U.S. government developed botulinum toxin for potential use as a weapon during World War II. Japan, Iraq, and the Soviet Union have also experimented with botulinum toxin as a biological weapon, and Iran, North Korea, and Syria may have done so as well.

However, scientists have been perplexed and terrorists thwarted by how difficult it is to prepare botulism toxin for use as a weapon. Terrorists in Japan attempted to unleash it on at least three occasions between 1990 and 1995, but their plan for widespread destruction failed each time. In addition to tracking the efforts of bioterrorists, the U.S. government has developed elaborate methods to detect and respond to an attack with botulinum toxin. A national surveillance system involving doctors and hospitals has been designed to alert the U.S. Centers for Disease Control and Prevention to botulism outbreaks, and stores of antitoxin are on hand to treat victims.

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botulism

botulism Rare, but potentially lethal, form of food-poisoning caused by a toxin produced by the bacterium Clostridium botulinum. The toxin attacks the nervous system, causing paralysis and cessation of breathing. The most likely source of botulism is imperfectly canned meat. Botulinum toxin (Botox) is used medicinally as a treatment for some neuromuscular disorders and in plastic surgery.

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botulism

botulism (bot-yoo-lizm) n. a serious form of food poisoning from foods containing the toxin produced by the bacterium Clostridium botulinum, which thrives in improperly preserved foods. The toxin selectively affects the central nervous system; some cases are fatal.

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botulinum toxin

botulinum toxin A nerve toxin produced by the bacterium Clostridium botulinum, which can cause fatal food poisoning. It is the most toxic substance known. In minute doses it is used to treat certain conditions involving muscle dysfunction.

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